Method of piercing air suction holes in abrasive sheet material

ABSTRACT

Apparatus including a portable sander having a power driven shoe adapted to carry a sheet of sandpaper or the like and containing suction holes through which air and abraded particles are drawn by suction to a collection bag, and a coacting piercing tool adapted to punch suction holes in a sheet of sandpaper carried by the shoe when the sander and piercing tool are moved relatively toward one another.

United States Patent 1191 Hutchins METHOD OF PIERCING AIR SUCTION HOLES IN ABRASIVE SHEET MATERIAL [76] Inventor: Alma A. Hutchins, 49 N Lotus Ave., Pasadena, Calif. 91107 22 Filed: July 16, 1973 21 Appl. 110.; 379,209

Related US. Application Data [62] Division of Ser. No. 282,155, Aug. 21, 1972, Pat. No.

1111 3,866,304 [4 1 Feb. 18, 1975 2,115,543 4/1938 Thackray 156/253 X 2,160,374 5/1939 Veillett'e 29/432 UX 2,856,680 10/1958 Johnson et al. 29/432 3,205,112 9/1965 Gilbert 156/253 3,638,362 l/1972 Stoll 51/273 X Primary Examiner-Charlie T. Moon Attorney, Agent, or Firm-William P. Green 3,788,011. [57] ABSTRACT Apparatus including a portable sander having a power 29/445 g 33 driven shoe adapted to carry a sheet of sandpaper or [58] Field the like and containing suction holes through which 93/1 1 l 156/253 51 air and abraded particles are drawn by suction to a 6 273 collection bag, and a coacting piercing tool adapted to punch suction holes in a sheet of sandpaper carried by [56] References Cited the shoe when the sander and piercing tool are moved relatively toward one another. UNITED STATES PATENTS 1,800,341 4/1931 Davies 51/170 R 3 Claims, 5 Drawing Figures a: l a 5),:-

METHOD OF PIERCING AIR SUCTION HOLES IN ABRASIVE SHEET MATERIAL CROSS REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION This invention relates generally to portable power driven work abrading tools, such as sanders and the like.

In my above identified copending application, I have disclosed a type of portable abrading tool having a power driven shoe or other element which removably carries a sheet of sandpaper or the like, and having suction means associated with the tool for creating a vacuum at the work surface acting to withdraw air and dust particles abraded from the work to a collection location, such as an appropriate collection bag. The suction system of that application preferably takes suction through openings formed in the power driven element and through communicating openings formed in the sandpaper, so that air may be drawn through these openings into the interior of the tool for delivery to the collection location.

SUMMARY OF THE INVENTION The present invention relates to improved apparatus and methods for forming suction openings of this type in a sheet of sandpaper or the like. To assure proper positioning of the openings in the sandpaper, directly opposite and in registry with the openings in the carrying element itself, I first attach the sandpaper in unperforated form to that element, and then after such attachment pierce holes in the sandpaper at precisely the proper locations of communication with the openings in the carrier element. Such formation of the openings in the sandpaper after attachment of the paper to the carrier avoids the necessity for precise accuracy in locating the sandpaper on the carrier, such as would be required if the openings in the sandpaper were preformed and had to then be brought into exact positions of registry with the openings in the carrier at the time of attachment to the carrier. Further, this method substantially reduces the cost of the sandpaper, since completely conventional unperforated paper can be employed rather than a specially prepared prepunched sandpaper.

Certain particular features of the invention relate to a unique piercing tool, which has projections arranged in a predetermined pattern and designed to form openings in a sheet of sandpaper carried by the tool, with the openings being at precisely the proper locations for communication with the discussed suction openings or passages formed in the carrier itself. Appropriate locating means are provided on the piercing tool, for locating the sander and piercing tool laterally relative to one another in a proper orientation for forming the desired hole pattern. These locating means may include one or more locating flanges formed on the piercing tool, de-

sirably at least two such flanges, for engagement with peripheral edges of a shoe of the sander in locating relation. Preferably, the piercing tool is secured to a mounting structure in fixed position, so that an operator may pierce holes in the sandpaper by merely pressing the sander manually against the'stationary piercing tool.

BRIEF DESCRIPTION OF THE DRAWING The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawing, in which:

FIG. 1 is a perspective representation of a sander and piercing tool combination constructed in accordance with the invention;

FIG. 2 is an enlarged fragmentary vertical section taken essentially on line 2-2 of FIG. 1;

FIG. 3 is a bottom plan view of the sander taken on line 33 of FIG. 2;

FIG. 4 is a top plan view of the piercing tool taken on line 4-4 of FIG. 2; and

FIG. 5 is an enlarged fragmentary view showing the sander and piercing tool in their fully interfitting condition, at the end of a piercing stroke.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, there is shown at 10 a portable power driven sander carrying a sheet of sandpaper or other abrasive material 11, in which air suction openings are formed by a coacting piercing tool 12 which may be rigidly secured to the upper horizontal surface 13 of a workbench or other mounting structure 14. The sander may include a portable body structure 15 having suitable handles such as those shown at 16 and 17 for holding and manipulating the sander to abrade a work surface. A working shoe or carrier structure 18 is mounted movably to body 15, and is power driven relative thereto in any appropriate manner by a motor typically contained within body 15 and represented diagrammatically at 19 in FIG. 1. The shoe l8 and sandpaper are typcially illustrated as of rectangular configuration, and may be given any of the conventional known types of sanding motion relative to body 15, such as for example orbital movement about a vertical axis 20 perpendicular to the sandpaper sheet 11, or straight line reciprocating movement along a front to rear horizontal axis 120 parallel to the plane of sandpaper 11. It is also contemplated that if desired both the shoe and sandpaper may be circular in shape, and be given either simple rotary motion or orbital motion about an axis perpendicular to the plane of the sandpaper.

As seen in FIG. 2, the illustrated rectangular shoe- 18 includes a planar rectangular metal plate 21 which in FIG. 2 extends horizontally and carries at its underside a similarly rectangular layer of cushioning material 22, typically formed of a fairly soft resiliently deformable rubber or the like. The cushion 22 has a planar undersurface 23 against which the rectangular sandpaper sheet 11 is retained by means of a pair of clips 24 carried at the upper side of plate 21 and releasably retaining the opposite ends of the sandpaper. The upper surface 122 of cushion 22 may be appropriately cemented to plate 21.

The shoe assembly 18 contains a number of interior passages 25 through which air is drawn from the underside of the shoe and from adjacent the work surface into and through the shoe for ultimate delivery to a collection bag 26, which is porous to allow escape to air from the bag to the atmosphere while retaining collected dust particles therein. This movement of air and particles may be produced in any convenient manner, but is optimally produced by means of an aspirator which is represented at 27 in FIG. 1 and may be carried by body 15 of the tool. The motor 19 which drives the tool may be an air-driven motor, in which event the exhaust air from that motor may be delivered to an inner tube 127 of aspirator 27 (FIG. 2), and flow through that tube toward bag 26 as a primary air stream 227, which induces a aspirator action a secondary flow of air 327 upwardly through shoe 18 and into an outer tube 427 of the aspirator and then to bag 26 in admixture with the primary stream. Certain aspirator systems of this type are disclosed in detail in my above mentioned prior application Ser. No. 213,018.

The air passages 25 in shoe 18 may be formed as a number of vertically extending parallel passages 28 extending upwardly within the material of cushionbody 22 from its undersurface 23, and communicating at their upper ends with horizontal grooves or passages 29 formed in the upper surface of cushion body 22, beneath plate 21, in a pattern leading air from all of the passages 28 to a single upwardly projecting air discharge tube 30 connected to plate 21 and communicating with a flexible tube 31 leading to the aspirator 27. The shoe may be mounted to body 15 for the desired orbital, straight line or other movement in any convenient manner. Typically illustrated in FIG. 2 is an orbital arrangement in which the shoe is movably con- 1 nected to body 15 by a number of flexible rubber connector posts 32, and is driven orbitally about vertical axis 20 by a conventional orbital driving connection 33 between the rotor of motor 19 and shoe 18.

The different air suction passages or openings 28 formed in cushion 22 of the shoe may be arranged in any convenient pattern across the undersurface 23 of the shoe, as for instance in the pattern shown in FIG. 3, in which there are two rows of passages or openings extending along two parallel lines 34 and 35, near pposite parallel side edges 36 and 37 respectively of the rectangular shoe. Between these two rows of apertures, an intermediate or central row of apertures may be formed along a parallel line 38, typically with fewer apertures as seen in FIG. 3.

When the sandpaper sheet 11 is initially connected to the shoe of tool by clips 24, the sandpaper is imperforate. After such application of the sandpaper, apertures 39 are formed in the sandpaper directly opposite and in registry with the openings or passages 28 in the shoe, so that air may pass upwardly through openings 39 and then passages 28 for ultimate delivery to bag 26. These openings in the sandpaper are formed by the previously mentioned piercing tool 12. This piercing tool preferably includes a rigid horizontal base plate 40 typically formed of a suitable rigid planar piece of sheet metal, such as steel, having substantially the same rectangular horizontal outline configuration as does shoe 18 of the tool. That is, the base 40 may have two parallel opposite side edges 41 and 42 spaced apart essentially the same distance d as the opposite straight side edges 36 and 37 of the shoe, and may similarly have two transverse parallel straight opposite end edges 43 and 44 spaced apart substantially the same distance I as are the transverse opposite end edges 45 and 46 of the rectangular shoe. Along a portion of its peripheral edge, base plate 40 has one or more upstanding flanges which are engageable with the corresponding edges of the shoe for accurately locating the shoe relative to the base plate as the shoe is pressed downwardly toward that plate. Desirably, two such flanges are formed on the base plate at 47 and 48, extending along the two previously mentioned side and end edges 41 and 44, with these flanges projecting direclty upwardly perpendicular to base 40 and perpendicular to one another, and typically being formed by merely bending upwardly the edges of plate 40.

' At a number of different locations spaced across the area of base plate 40, this plate carries a series of upwardly projecting rigid pins or projections 49, which may be spot welded or otherwise rigidly secured at their lower ends to plate 40 and centered about individual parallel vertical axes 50. These pins may be cylindrical about axes 50 from the level of plate 40 upwardly to a location 140, beyond which the upper ends of the pins may be tapered conically at 51, as seen in FIG. 2, to form sharp points 52 at the upper ends of the pins capable of easily and quickly piercing openings in the sandpaper. These upper pointed ends of the various pins may lie in a common horizontal plane 53, disposed parallel to the planar base plate 40 of the piercing tool 12, but preferably spaced beneath the plane 54 in which the upper edges of flanges 47 and 48 lie. For best results, the distance m vertically between planes 53 and 54, that is, the distance that the flanges project upwardly beyond the tips of pins 49, should preferably be at least about A of the height h of pins 49, desirably at least about /a of that height, and for optimum results approximately 1% of the pin height.

The piercing tool 12 should be appropriately connectible to a suitable support, such as the illustrated workbench 14 of FIG. 1. For this purpose, the base plate 40 of the piercing tool may contain a number of spaced openings 55, typically four such openings in the pattern illustrated in FIG. 4, with fastening screws 56 extending through those openings and connecting into the workbench 14 or other horizontal support surface, to hold base plate 40 tightly against surface 13 of the workbench in fixed position relative thereto.

To now discuss the manner of use of the described sander and piercing tool combination, assume that the piercing tool has been connected to the workbench in the position illustrated in FIG. 1 and that there is initially no sandpaper on the sanding tool 10. The firt step then is to connect an initially imperforate sheet of sandpaper to the underside of shoe 18 of the sanding tool, and retain it in that position on the tool by extending the opposite ends of the rectangular sheet of sandpaper upwardly as shown in FIG. 2 for connection to and retention by clips 24. After the sandpaper has thus been secured to the shoe in taut condition, a user grasps handles 16 and 17 of the sander, and moves the sander to the FIG.'2 position in which the sandpaper and shoe 18 are directly above and parallel to the piercing tool. The sander is then moved downwardly toward plate 40 of the piercing tool, and as the shoe reaches the location of flanges 47 and 4.8 the corresponding edges 36 and 46 of the sander shoe are moved to positions in which they engage or abut laterally or outwardly against the inner surfaces of flanges 47 and 48 respectively, to thereby accurately locate the shoe relative to the piercing tool during the final portion of the downward movement of the sander. The pins 49 of the piercing tool are arranged in a pattern corresponding exactly to the pattern of openings 28 of the shoe, and are so located on the base plate that, when the shoe is positioned by engagement with flanges 47 and 48 as discussed above, each of the pins 49 will be directly vertically opposite a corresponding one of the passages or openings 28 in the shoe. Thus, as the operator presses the sander downwardly within piercing tool 12, and toward base plate 40, the pins 49 simultaneously pierce openings 39 in the initially imperforate sandpaper at the locations of shoe passages 28. The cylindrical portions of the pins have an external diameter corresponding substantially to the internal diameter of cylindrical shoe passages 28, so that the openings pierced in the sandpaper are of essentially the same diameter as passages 28 and are in exact registry therewith. Ultimately, the sandpaper carried at the underside of the shoe reaches a position of engagement with base plate 40, which position is illustrated for one of the pins in FIG. 5, and in which position pins 49 project upwardly into the corresponding cylindrical passages 28 in the shoe, typically to about the tops of those passages as shown. The operator may then lift the sander off of the piercing tool, and use the sander in conventional manner by placing it on a work surface and energizing motor 19 to actuate the shoe and sandpaper orbitally (or otherwise) in a sanding motion. During such operation, the suction system draws air and dust particles upwardly from the work surface through openings 39 and 28 to aspirator 27, and to bag 26 for collection therein.

While a certain specific embodiment of the present invention has been disclosed as typical, the invention is of course not limited to this particular form, but rather is applicable broadly to all such variations as fall within,

attaching a sheet of abrasive material to a power actuated movable section of a sander with said sheet adjacent an outer surface of said section through which a plurality of suction openings in a predetermined pattern extend for drawing air and abraded particles from the vicinity of a work piece;

said sheet at the time of initial attachment to said movable section being imperforate at the location of said suction openings;

positioning opposite said sheet of abrasive material a piercing tool having a plurality of piercing projectons arranged in a pattern corresponding to the pattern of said suction openings;

locating said piercing tool so that said projections are directly opposite and project toward said suction openings;

relatively moving said projections and said movable section and carried sheet toward one another and along an axis essentially perpendicular to said sheet while maintaining said projections in axial alignment with said suction openings; and

forcing said projections through said sheet at the locations of said suction openings by said relative movement between the projections and movable section and carried sheet to form apertures in the sheet aligned with and communicating with said uct uzpsa r n saislt s xab e SQFt Q 2. The method as recited in claim 1, in which said locating of the piercing tool is effected by moving predetermined locating portions of said movable section and said tool laterally against one another in at least two different directions transversely of said axis to align said projections axially with said suction openings.

3. The method as recited in claim 1, including securing said piercing tool to a mounting structure in essentially fixed position; and effecting said relative axial movement between said projections and said movable section and carried sheet by manually moving the sander axially toward and against the piercing tool and said projections thereof. 

1. The method that comprises: attaching a sheet of abrasive material to a power actuated movable section of a sander with said sheet adjacent an outer surface of said section through which a plurality of suction openings in a predetermined pattern extend for drawing air and abraded particles from the vicinity of a work piece; said sheet at the time of initial attachment to said movable section being imperforate at the location of said suction openings; positioning opposite said sheet of abrasive material a piercing tool having a plurality of piercing projectons arranged in a pattern corresponding to the pattern of said suction openings; locating said piercing tool so that said projections are directly opposite and project toward said suction openings; relatively moving said projections and said movable section and carried sheet toward one another and along an axis essentially perpendicular to said sheet while maintaining said projections in axial alignment with said suction openings; and forcing said projections through said sheet at the locations of said suction openings by said relative movement between the projections and movable section and carried sheet to form apertures in the sheet aligned with and communicating with said suction openings in said movable sectiin.
 2. The method as recited in claim 1, in which said locating of the piercing tool is effected by moving predetermined locating portions of said movable section and said tool laterally against one another in at least two different directions transversely of said axis to align said projections axially with said suction openings.
 3. The method as recited in claim 1, including securing said piercing tool to a mounting structure in essentially fixed position; and effecting said relative axial movement between said projections and said movable section and carried sheet by manually moving the sander axially toward and against the piercing tool and said projections thereof. 